Estimated GFR (eGFR)
eGFR is the clinically useful measure of kidney filtration capacity. It is the threshold metric for diagnosing chronic kidney disease.
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What it measures
Glomerular filtration rate is the volume of plasma your kidneys filter per minute. True GFR can only be measured by clearance studies; routine labs report an ESTIMATED GFR derived from your serum creatinine, age, sex, and (in older formulas) race. The CKD-EPI 2021 equation is now the standard and intentionally drops race as a variable. eGFR is what kidney disease classification is built on (KDIGO stages G1–G5), and it tracks much better than creatinine alone — a serum creatinine of 1.0 means very different things at age 25 vs age 75.
What a high value can mean
- Hyperfiltration — sometimes seen in early diabetes (before nephropathy), pregnancy.
- High muscle mass overestimating clearance — limitation of creatinine-based eGFR.
- Rarely clinically actionable in the high direction.
What a low value can mean
- eGFR 60–89 — mildly reduced; often age-related, monitored.
- eGFR 45–59 (CKD G3a) — moderately reduced; primary-care management plus annual specialist input.
- eGFR 30–44 (CKD G3b) — nephrology referral.
- eGFR <30 (CKD G4–G5) — advanced kidney disease; preparation for renal replacement planning.
- Causes: diabetes, hypertension, glomerulonephritis, obstruction, drug toxicity.
When to discuss with a doctor
A single low eGFR isn't a diagnosis — chronic kidney disease requires the reduction to persist for ≥3 months. Sustained eGFR <60 warrants primary-care work-up: urine albumin/creatinine ratio, blood pressure control, medication review (avoid NSAIDs, dose-adjust as needed). eGFR <30 needs a nephrologist. Mediora.AI plots your eGFR trajectory; treatment is highly individualised.